Wireless communication systems generally divide the time axis into continuing intervals of equal duration called frames. As shown in FIG. 1, a frame 100 is divided into a finite number (Nt) of intervals of equal duration called timeslots. A particular base station (or transceiver in the case of a sectored deployment) may use some or all of the timeslots for uplink or downlink transmissions as defined by the base station's timeslot assignment (i.e. the timeslots within each frame that have been allocated for uplink or downlink user traffic). In each timeslot, a finite number of codes (Nc) may be assigned for transmission/reception of voice and/or data (hereinafter “calls”). The timeslot(s) and code(s) assigned for a particular call (either in the downlink or the uplink) may be referred to as the physical channel(s) on which the call is being carried.
When a new call is initiated, a radio resource management (RRM) device determines the timeslot(s) and the number of codes in each timeslot that will be assigned to the new call. Typically, codes and timeslots are assigned either sequentially or at random. That is, referring now to FIG. 2, assume based on interference (e.g. which timeslots are being used for user traffic in neighboring cells) and/or traffic volume considerations that four particular timeslots 202, 204, 206, 208 within a particular frame have been allocated for handling uplink traffic. It is noted that although the four timeslots are shown for simplicity as being adjacent to each other, this is of course not necessary.
Where resources are assigned sequentially, the first code of a new call is assigned to the first timeslot 202. Additional codes (of the new call and subsequent calls where possible) are also assigned to timeslot 202 until no more codes may be assigned to timeslot 202 because, for instance, adding any more codes to timeslot 202 would degrade the signal-to-noise ratio or violate the maximum allowed transmit power constraint in the timeslot 202. Once timeslot 202 is no longer able to accept additional codes, further codes are assigned to timeslot 204 until it can no longer accept any more codes. This pattern continues for timeslots 206 and 208, as needed.
Where resources are assigned randomly, timeslots and codes are simply chosen at random. That is, in FIG. 2, a new call may have any of its codes assigned to any of the four timeslots assuming the conditions in the timeslots are sufficient for acceptance of codes.
Neither sequential nor random timeslot assignment is an efficient use of the timeslots that have been allocated for uplink and downlink user traffic because they fail to consider the conditions in the allocated timeslots. Therefore, it is desirable to have a method and system without such limitations.